<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        /* 弹性容器 */
        .box {
            display: flex;
            height: 300px;
            border: 1px solid #000;
        }

        /* 弹性盒子：沿着主轴方向排列 */
        .box div {
            width: 200px;
            /* height: 100px; */
            background-color: pink;
        }
    </style>
</head>
<body>
    <div class="box">
        <div>1</div>
        <div>2</div>
        <div>3</div>
        <div>1</div>
        <div>2</div>
        <div>3</div>
        <div>1</div>
        <div>2</div>
        <div>3</div>
    </div>
</body>
</html>                  